Grade Eight
Science Content Standards.
Focus on Physical Science
Motion
1.
The velocity of an object is the rate of change of its position. As a
basis for understanding this concept:
a.
Students know position is defined in relation to some
choice of a standard reference point and a set of reference
directions.
b.
Students know that average speed is the total distance
traveled divided by the total time elapsed and that the
speed of an object along the path traveled can vary.
c.
Students know how to solve problems involving distance,
time, and average speed.
d.
Students know the velocity of an object must be described
by specifying both the direction and the speed of the
object.
e.
Students know changes in velocity may be due to changes
in speed, direction, or both.
f.
Students know how to interpret graphs of position versus
time and graphs of speed versus time for motion in a single
direction.
Forces
2.
Unbalanced forces cause changes in velocity. As a basis for
understanding this concept:
a.
Students know a force has both direction and magnitude.
b.
Students know when an object is subject to two or more
forces at once, the result is the cumulative effect of all the
forces.
c.
Students know when the forces on an object are balanced,
the motion of the object does not change.
d.
Students know how to identify separately the two or more
forces that are acting on a single static object, including
gravity, elastic forces due to tension or compression in
matter, and friction.
e.
Students know that when the forces on an object are
unbalanced, the object will change its velocity (that is, it will
speed up, slow down, or change direction).
f.
Students know the greater the mass of an object, the more
force is needed to achieve the same rate of change in
motion.
g.
Students know the role of gravity in forming and
maintaining the shapes of planets, stars, and the solar
system.
Structure of Matter
3.
Each of the more than 100 elements of matter has distinct
properties and a distinct atomic structure. All forms of matter are
composed of one or more of the elements. As a basis for
understanding this concept:
a.
Students know the structure of the atom and know it is
composed of protons, neutrons, and electrons.
b.
Students know that compounds are formed by combining
two or more different elements and that compounds have
properties that are different from their constituent elements.
c.
Students know atoms and molecules form solids by
building up repeating patterns, such as the crystal structure
of NaCl or long-chain polymers.
d.
Students know the states of matter (solid, liquid, gas)
depend on molecular motion.
e.
Students know that in solids the atoms are closely locked
in position and can only vibrate; in liquids the atoms and
molecules are more loosely connected and can collide with
and move past one another; and in gases the atoms and
molecules are free to move independently, colliding
frequently.
f.
Students know how to use the periodic table to identify
elements in simple compounds.
Earth in the Solar S ystem (Earth Sciences)
4.
The structure and composition of the universe can be learned from
studying stars and galaxies and their evolution. As a basis for
understanding this concept:
a.
Students know galaxies are clusters of billions of stars and
may have different shapes.
b.
Students know that the Sun is one of many stars in the
Milky Way galaxy and that stars may differ in size,
temperature, and color.
c.
Students know how to use astronomical units and light
years as measures of distances between the Sun, stars,
and Earth.
d.
Students know that stars are the source of light for all
bright objects in outer space and that the Moon and
planets shine by reflected sunlight, not by their own light.
e.
Students know the appearance, general composition,
relative position and size, and motion of objects in the solar
system, including planets, planetary satellites, comets, and
asteroids.
Reactions
5.
Chemical reactions are processes in which atoms are rearranged
into different combinations of molecules. As a basis for
understanding this concept:
a.
Students know reactant atoms and molecules interact to
form products with different chemical properties.
b.
Students know the idea of atoms explains the conservation
of matter: In chemical reactions the number of atoms stays
the same no matter how they are arranged, so their total
mass stays the same.
c.
Students know chemical reactions usually liberate heat or
absorb heat.
d.
Students know physical processes include freezing and
boiling, in which a material changes form with no chemical
reaction.
e.
Students know how to determine whether a solution is
acidic, basic, or neutral.
Chemistr y of Living S ys tems (Life Sciences)
6.
Principles of chemistry underlie the functioning of biological
systems. As a basis for understanding this concept:
a.
Students know that carbon, because of its ability to
combine in many ways with itself and other elements, has
a central role in the chemistry of living organisms.
b.
Students know that living organisms are made of
molecules consisting largely of carbon, hydrogen, nitrogen,
oxygen, phosphorus, and sulfur.
c.
Students know that living organisms have many different
kinds of molecules, including small ones, such as water
and salt, and very large ones, such as carbohydrates, fats,
proteins, and DNA.
Periodic Table
7.
The organization of the periodic table is based on the properties of
the elements and reflects the structure of atoms. As a basis for
understanding this concept:
a.
Students know how to identify regions corresponding to
metals, nonmetals, and inert gases.
b.
Students know each element has a specific number of
protons in the nucleus (the atomic number) and each
isotope of the element has a different but specific number
of neutrons in the nucleus.
c.
Students know substances can be classified by their
properties, including their melting temperature, density,
hardness, and thermal and electrical conductivity.
Densit y and Buo yanc y
8.
All objects experience a buoyant force when immersed in a fluid. As
a basis for understanding this concept:
a.
Students know density is mass per unit volume.
b.
Students know how to calculate the density of substances
(regular and irregular solids and liquids) from
measurements of mass and volume.
c.
Students know the buoyant force on an object in a fluid is
an upward force equal to the weight of the fluid the object
has displaced.
d.
Students know how to predict whether an object will float or
sink.
Investigation and Experimentation
9.
Scientific progress is made by asking meaningful questions and
conducting careful investigations. As a basis for understanding this
concept and addressing the content in the other three strands,
students should develop their own questions and perform
investigations. Students will:
a.
Plan and conduct a scientific investigation to test a
hypothesis.
b.
Evaluate the accuracy and reproducibility of data.
c.
Distinguish between variable and controlled parameters in
a test.
d.
Recognize the slope of the linear graph as the constant in
the relationship y=kx and apply this principle in interpreting
graphs constructed from data.
e.
Construct appropriate graphs from data and develop
quantitative statements about the relationships between
variables.
f.
Apply simple mathematic relationships to determine a
missing quantity in a mathematic expression, given the two
remaining terms (including speed = distance/time, density
= mass/volume, force = pressure × area, volume = area ×
height).
g.
Distinguish between linear and nonlinear relationships on a
graph of data.